1. Field of the Invention
The present invention relates to a thermo-sensitive transfer ink ribbon to be used in producing a dry type transfer material for thermally transferring an ink image from the surface thereof onto a target transferring material by using a printer, a typewriter, a word processor, or the like, of the thermo-sensitive transfer system. The present invention further relates to a method of producing such a thermo-sensitive transfer ink ribbon.
2. Description of the Prior Art
Recently, printing apparatus such as a printer, a typewriter, a word processor, etc., of the thermo-sensitive transfer system has been developed, and used widely from in a field of small-scaled personal use to in a field of large-scaled business use. Printing according to this thermo-sensitive transfer system is performed in such a manner that a thermo-sensitive transfer ink ribbon is made to come into close contact with predetermined printing paper by a thermal head and selected ones of a large number of heating resistor elements of the thermal head are energized so as to fuse heat-fusible ink portions contacting with the selected heating resistor elements through a support of the thermo-sensitive transfer ink ribbon so that an ink image is thereby transferred onto the printing paper.
Such a conventional thermo-sensitive transfer ink ribbon of the type as described above, however, has been formed of a predetermined support coated with only heat-fusible ink composed of a coloring agent and a binder agent which contains wax as a principal component. Further, the thermo-sensitive transfer ink ribbon of the type as described above has been utilized only when ordinary paper is used as a target material for transfer.
Recently, as the thermally-sensitive transfer system has been popularized, an improvement in property of transfer to rough paper (paper having low smoothness) has been required, and various patent applications related to the foregoing requirement have been filed. Further, there have been proposed various techniques, for example, related to a multi-time ribbon with which transfer and printing can be repeatedly performed by using one and the same ink ribbon, a correctable ribbon with which errors in printing can be erased and corrected, and so on.
As far as the inventors of this application know, however, any report has not been given as to a thermo-sensitive ink ribbon for making it possible to perform transfer and printing onto a surface having poor wettability and having good mold-releasing and peeling properties. Moreover, since the thermo-sensitive transfer system has not been used at all as means for producing a dry type transfer material for use for instant lettering, there has been proposed no thermo-sensitive transfer ink ribbon to be used for producing a dry type transfer material for use for instant lettering. Accordingly, it is a matter of course that there has been proposed no method of producing such a thermo-sensitive transfer ink ribbon to be used for producing a dry type transfer material for use for instant lettering.
In order to perform thermo-sensitive transfer of an image on a printing surface having poor wettability and having a good mold releasing property, the printing surface is required to be separated from an ink ribbon before ink has been dried. To this end, it is necessary that thermal efficiency of a thermo-sensitive transfer apparatus is improved or an energy applied thereto is increased, or, alternatively, that ink is lowered in its melting point, fusion viscosity, and cohesion strength. It is not easy to increase the thermal efficiency of a thermo-sensitive transfer apparatus and there is a limit in increasing the thermal efficiency. Further, there is also a limit in increasing the energy for the thermo-sensitive transfer apparatus. On the contrary, in the existing circumstances, it is desired to reduce the energy, in view of the life of a head and a load to the apparatus. Regarding the ink, on the other hand, in the case of using ink having a low melting point, low fusion viscosity, and small cohesion strength, there is a problem in that a thermo-sensitive transfer image is spread, the ink is raked up by pressure of a head, or at the time of pressure-sensitive transfer, the image is partially transferred or is extended.